top-down model

top-down model

One of two proposed morphologic pathways of spontaneous development of adenomas. The top-down model is based on observations of dysplastic cells only located at the luminal surface of the crypts, along with migration of adenomatous cells from the surface to the base of a crypt. In this model, an initial stem cell mutation is thought to occur in the epithelial mucosa situated in the intra-cryptal zone between 2 crypt orifices, with subsequent stem cell division producing a mutant clone that expands laterally and downwards into the crypt, displacing normal epithelial cells.

Also, by having more bottom-up organizing, we're enabling local organizers to rise to positions of leadership much more quickly than with the old top-down model, where you have to wait your turn and "sit in all the chairs," so to speak, before you are given the chance to lead.

Therefore, this top-down model, Rose suggests, actually sowed the seed for the resurfacing of war-related problems after the 1980s when reconciliation became pluralized and began to incorporate other nongovernmental actors.

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